Irradiation effects on hardness and phase stability were investigated for an FeCr(Y, Ti)-ODS ferritic steel strengthened by Y-Ti-O nano-particles after irradiation with 6.4 MeV Fe³⁺ at room temperature (RT) up to nominal damages of 2, 10 and 50 dpa. With increasing local displacement damage up to ∼20 dpa, nano-sized oxide particles slightly shrank, while the corresponding number density drastically decreased by almost two orders of magnitude compared to that of before irradiation. It is considered that ballistic dissolution should be responsible for such reductions in the particle size and number density. Dislocation loops consisting of 1/2<111> type (>80%) and <100> type were observed under weak beam dark field (WBDF) imaging condition in the specimen irradiated to the nominal damage of 50 dpa. The average size and number density of all the dislocation loops were 2.8 ± 0.7 nm and (4.1 ± 0.7) × 10²² m⁻³, respectively, at the local damage of ∼72 dpa. Although the oxide particles were almost completely dissolved, nanoindentation hardness measurements revealed that the hardening went up continuously with increasing displacement damage and was estimated to be 1.63 ± 0.39 GPa by the Nix-Gao model at the nominal damage of 50 dpa. The irradiation hardening accompanied by the dissolution of oxide particles was interpreted in terms of loss of oxide particles, solid solution hardening and formation of fine dislocation loops. The contribution of dislocation loops observed by transmission electron microscopy (TEM) to the hardening was insufficient to overcome the loss of strengthening by dissolution, suggesting the importance of solid solution hardening and the larger strength factor of dislocation loops as a hardening contributor.

研究了用6.4 MeV Fe ³⁺辐照Y-Ti-O纳米粒子增强的FeCr（Y，Ti）-ODS铁素体钢的辐照对硬度和相稳定性的影响。在室温（RT）时，标称损坏为2、10和50 dpa。随着局部位移损伤的增加直至约20 dpa，纳米级氧化物颗粒略微收缩，而与辐照前相比，相应的数密度急剧降低了近两个数量级。人们认为，弹道溶解应是造成粒度和数量密度降低的原因。在弱光束暗场（WBDF）成像条件下，在标称损伤为50 dpa的标本中，观察到由1/2 <111>型（> 80％）和<100>型组成的位错环。所有位错环的平均大小和数密度为2.8±0.7 nm和（4.1±0.7）×10 ²²  m ^-3分别在〜72 dpa的局部破坏下。尽管氧化物颗粒几乎完全溶解，但纳米压痕硬度测量表明，随着位移损伤的增加，硬化程度不断提高，根据Nix-Gao模型在标称损伤为50 dpa时估计为1.63±0.39 GPa。用氧化物颗粒的损失，固溶体硬化和精细的位错环的形成来解释伴随氧化物颗粒溶解的辐射硬化。通过透射电子显微镜（TEM）观察到的位错环对硬化的贡献不足以克服溶解引起的强化损失，这表明固溶硬化的重要性以及位错环作为硬化成分的更大强度因子。